Engine starter liquid lock detector



Jan. 10, 1950 I s, RT 2,494,385

ENGINE STARTER LIQUID LOCK DETECTOR Filed May 10, 1948 mull INVEN TOR.

. SAMUEL G/LBEPT BY fim Y fir/DR V Patented Jan. 10, 1950 ENGINE. STARTER LIQUID LOCK DETECTOR Samuel Gilbert, Cedar Grove, N. J., assignor to Bendix Aviation Corporation, a corporation of Delaware Teterboro, N J-.,1

Application May 10, 1948,, Serial No. 26,135

6 Claims. (01. 7.4-7)

The present invention relates to apparatus for detecting a liquid lock in, and/or scavenging the look from, an inverted cylinder of an aircraft radial engine or the like, which apparatus opcrates" without damage to the engine or itself, and: is effective to start the engine when a liquid lock is not present, or has been scavenged.

The present invention is an improvement over the device of copending application of Romeo M.. Nardona: Serial. No. 527,422, filed March 21, 1 944,. for scavenging meansfor aircraft engines now Patent No. 2,447,912, and assigned to the assignee hereof.

When anairplane is parked, theengine oil or other liquid, such as a mixture ofoil', fuel and water, sometimes occurring, gravitates toward the lower or invertedcylinders, and accumulates in quantity and condition: dependent upon the amount of. liquid present, the period of parking, the tightness of piston rings, the temperature, and other conditionsexisting at thetime. Widely different results may thus occur, such that just prior to starting, there may be" noappreciable accumulation, no resulting liquid lock, only a small congealed or highly or congealed lock, or. any of such conditions.

Ordinarily, if a serious look exists, and the starter is operated. in the usual manner in an attempt to start the engine, one of two results may occur... If, during; attempted starting, firing occurs prior tohitting the look at the starter speed, the lock will be hit under the power of the engine, which will immediately so damage the engine as to render it.- useless. damage, other than adverse results possibly of several combinations caused by the failure to start, may be confined to the engine, and not extended to other parts of the plane or its contents.

However, if the lock is hit at the starter speed under the lesser power of the starter-motor, the engine, although not completely disabled, may be seriously damaged in a manner not immediately apparent. In any event, the propeller stops, thus indicating a lock, which may be scavenged as by spark plug removal, and subsequent starting successfully effected. Thus, the engine, although not completely disabled, as in the first instance, so that take off cannot occur, may be so damaged that failure will occur in the air, so that Wrecking the engine, as in the first instance, may be the lesser evil of the two. e

To more safely determine whether a lock exists, it has been required to turn the engine over slowly, prior to starting, as by manually-turm Thus, the

the ground.

instance, where about isnow'the chosen speed.

and the like. adapted for mounting at any position about its placement are greatly facilitated mounting and by its. lack 'of' interference with surrounding structure by protuberances.

flexible shaft.

ing the propellers and, as in the specific example shown by the above-mentioned copending application, by the provision of means including an auxiliary motor;

The manual method, which is effected by having attendants hang on the propellers, is notonly very troublesome, inefiicient and wasteful of manpower and time, but is extremely dangerous, since it has resulted in injury and loss of life, particularly in connection with large bomber planes, where the propellers are so high from more than two revolutions per minute, and probably preferably less than this, as in the present one revolution per minute Also, with a four-cycle engine, it has been required to thus slowly turn the engine shaft through two complete, or nearly complete, revolutions to guard against the possibility of having any of the lower" pistons fail to attempt to go through a complete stroke corresponding to a compression stroke, where all valves areclcsed, and where, as a result, if the stroke were not completed at least as far as hitting an existing lock, the procedurewould be i'nefiective.

1 Present airplane starters have developed toa type having fairly symmetrical cylindriform overall contour, extending from the engine as a cantilever structure and free from appreciable protuberances larger than necessary terminals A starter of' such type is better axis, conserves space. in the airplane, for shipping and storing the starter, and its assembly and reby its end Because of the cantilever form, th starter cannot exceed a certain length or be unduly weighted near its outer end; without danger of impairment from lateral vibration effect which is magnified at the outer end.

It has heretofore been further suggested, relative to the additional motor above-mentioned, that instead of being mounted directly on the cantilever starter, it be mounted elsewhere on the plane and connected to the starter as by a The latter structure, as in the case of the form wherein the additional motor is mounted directly on the starter, may, with slight change and expense, be applied to existin starters not so equipped. However; in the case of the separately mounted motor also, the additional space required, the separably manipulable character of the parts, and other factors are unfavorable in certain applications, particu larly in the light of the invention hereof.

An object of the present invention is to overcome all of the disadvantages of the above-mentioned prior apparatus, and to do so by novel effective means.

Another object is to provide a complete selfcontained unit for the indicated purposes which, like the above-mentioned cylindriform cantilever structure, may have such form, and contain all necessary parts locally therein, as distinguished from a starter requiring any like auxiliary apparatus mounted either on the starter, or remotely therefrom, and connected thereto.

Another object is to provide a lock detector starter device in which a single motor is adapted to effect certain results of the two motors abovementioned.

Another object is to provide a device of the character indicated in which one element, such as a motor shaft, is operable, in one direction, to effect the lock-indicating function and, in the opposite direction to start the engine.

Another object is to provide a novel starter combination between a primary or motor shaft, a pinion shaft, an auxiliary gear train, and overrunning clutch means.

Another object is to provide a device, of the above-indicated character, which is simple and durable in construction, economical to manufacture, and effective in its operation.

. Another object is to provide a combined lock detector and starter having two gear trains, one of which is operable individually and with the other, and both are located between the primary starter drive means and the engine-engaging starter member.

The above and other objects and features of the invention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawing wherein one embodiment of the invention is illustrated by way of example.

In the drawing:

The single figure is a side view, partially in elevation and partially in section, of a device constructed in accordance with one form of the invention.

Referring to the drawing, H) comprises a member or jaw end of the starter, the left end as shown,

an engine starter l2 at the front adapted to rotate an engine element complimentary to the jaw i2 to start the engine.

A'motor l4 includes a reversible armature or rotor is rotative with a hollow shaft 18, and has bearings 26 and 22 for the rotor shaft l8 adjacent to the front and rear ends, respectively, of the rotor l6.

A pinion 24, forwardly of bearing 20, has a shaft 26 extending rearwardly from the pinion through and beyond, the inner end of the rotor shaft 18.

Usual means 30, between the pinion 24 and the jaw member 12, includes, in this instance, a three stage front gear train 32, a torquelimiting friction disc pack 34, a hollow spline nut 36, a screw shaft 38, and other elements for driving the member l2 by the pinion 24 at a speed for starting the engine.

The device further comprises a rear gear-train bearing 44, a rear gear train 46, between the rear rotor bearing 22 and thegear train bearing 44,

having an input gear 48 connected to the rotor shaft 18 and an output gear 50 journaled in the rear gear train bearing 44.

Clutch means 52 includes an overrunning clutch 54, as of the sprag type, between the input gear 48 and the pinion shaft 26, and another or similar overrunning clutch 56 between the output gear 50 and the pinion shaft 26.

In operation, the arrangement is such that, when the motor [4 is energized to cause rotation of the shaft 18 in starting direction, the clutch 54 causes the pinion shaft 26 to rotate in starting direction, free from the gear train 46, which, at this time, is idling relative to the pinion shaft 26 through the overriding clutch 56. With the shaft l8 thus rotating in starting direction, the pinion 24 drives the member [2 through the means 30 at the engine starting speed.

When the motor 14 is energized to cause rotation of the shaft 18 in the opposite direction, the clutch 54 slips relative to the pinion shaft 26 and the input gear 48 transmits motion through the rear gear train 46, the output gear 50, and the clutch 56, to the pinion shaft 26. This action turns the pinion shaft 26 in the same direction as the shaft was turned through the clutch 54, but at the reduced speed effected by the rear gear train 46, and since the operation from the pinion 24 to the jaw member I2 is the same as in starting, the member [2 is turned in the same direction as in starting, but at the prescribed speed reduced sufficiently below the starting speed to indicate and/or scavenge a hydraulic look from an inverted cylinder of the engine free from damage.

A housing unit 66 comprising parts62, 64, 66 and 68, is of generally cylindriform character free from substantial protuberances larger than necessary terminals, such as a motor terminal H1. The housing part 64 has a flange I2 by which the starter I6 is adapted for mounting, adjacent to the end housing portion 62, on an engine, with the major portion of the starter projecting from the flange l2 outwardly from the engine as a cantilever structure. All of the working parts are within the housing unit 60, with the jaw member [2 protruding from the inner end or bafile housing portion 62.

Although only one embodiment of the invention has been illustrated and described, various changes in the form and relative arrangements of the parts may bemade to suit requirements.

What'is claimed is:

1. In combination in an engine starter, a starter member at the front end of the starter adapted to rotate an engine element to start the engine, a motor including a reversible rotor having a hollow shaft, bearings for the shaft, forwardly and rearwardly of the rotor, a pinion forwardly of the front bearing having a shaft extending rearwardly through and beyond the inner end of the rotor shaft, means between the pinion and the starter member including a front gear train for driving the starter member by the pinion at a speed for starting the engine, a rear geartrain bearing, a rear gear-train between the rear rotor bearing and the gear-train bearing having an input gear connected to the rotor shaft and an output gear journaled in the rear gear-train bearing, and clutch means including an overrunning clutch between the input gear and the pinion shaft and an 'overrunning clutch between the output gear and the pinion shaft and responsive to rotation of the rotor shaft in starting direction for causing the starter member to rotate in starting direction at the engine starting speed and to rotation of the rotor shaft in the opposite direction for rotating the starter member in starting direction at a speed sufficiently reduced from the starting speed to indicate and/or clear a hydraulic look from an inverted cylinder of the engine free from damage.

2. The combination with an engine starter comprising a housing unit of generally cylindriform character free from substantial protuberances and adapted for mounting adjacent to one end on an engine with a major portion projecting from the engine as a cantilever structure, a member in and protruding from the inner end of the housing unit for rotating an engine element to start the engine, means including a shaft in the housing unit for driving the member, and speedreducing means in the housing unit, the shaft and the member being adapted for cooperation with said speed-reducing means for translating reduced from said starting speed to turn the engine over at a rate to prevent damage from a hydraulic lock in an inverted cylinder of the engine and including second speed-reducing means adapted to operate through the intermediary of said first speed-reducing means, and means adapted to render said second speed-reducing starting speed and driving direction of the memthe speed of the shaft into engine-starting speed 1 of the member, of means disposed in the housing unit providing for driving the member at a speed sufliciently reduced from said starting speed to turn the engine over at a rate to prevent damage from a hydraulic lock in an inverted cylinder of the engine and including second speed-reducing means adapted to operate through the intermediary of said first speed-reducing means, and means adapted to render said second speed-reducing means effective and ineffective, respectively, relative to said first speed-reducing means.

3. The combination with an engine starter comprising a member adapted to rotate an engine element to start the engine, and means including a gear train for rotating the member, of a motor including a reversible rotor having a hollow shaft, a pinion meshing with a gear of said train and having a shaft extending through the rotorshaft, a second gear train having an input gear connected to the rotor shaft and an output gear, and overrunning clutch means between the pinion shaft and the input and output gears, respectively, and responsive to rotation of the rotor shaft in opposite directions for causing rotation of the member in starting direction at a starting speed and at a speed reduced from starting speed, respectively, the reduced speed affecting the member to operate the engine to indicate a hydraulic lock in an inverted cylinder of the engine.

4. The combination with an engine starter including a motor, a member adapted to be driven by the motor to rotate an engine element to start the engine, and speed-reducing means, the motor and the member being adapted for cooperation with said speed-reducing means for translating the speed of the motor into engine starting speed of the member, of means providing for driving the member by said motor at a speed sufllciently her, and means providing for driving the member in starting directionat a speed sufiiciently reduced from the starting speed to turn the engine over at a rate to prevent damage from a hydraulic lock in a cylinder of the engine and including second speed-reducing means adapted in response to rotation of the shaft in the opposite direction to operate through the intermediary of the first speed-reducing means.

6. The combination with an engine starter including a rotatable driving shaft, a member adapted to be driven by the shaft to rotate an engine element to start the engine, and speedreducing means, the shaft and the member being adapted for cooperation with said speed-reducing means for translating the speed of the shaft into engine starting speed of the member, of means providing for driving the member at a speed sufficiently reduced from said starting speed to turn the engine over at a rate to prevent damage from a hydraulic lock in an inverted cylinder of the engine and including second speed-reducing means adapted to operate between the shaft and the member through the intermediary of said first speed-reducing means, and means adapted to render said second speed-reducing means effective. and ineffective, respectively, relative to said first speed-reducing means.

SAMUEL GILBERT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,002,413 Nardone May 21, 1935 2,036,073 OHagan Mar. 31, 1936 2,273,626 Connell Feb. 17, 1942 

